With technological developments, multimedia communications are more and more widely applied in mobile communications. Current multimedia communications are not simple video and audio communications, but also include services like instant messaging, co-address browsing, cooperative work, streaming media, etc. In particular, services combining new communication means and traditional voices together are becoming more and more popular with subscribers.
Based on a trend that Internet and conventional telecommunication networks are converged increasingly at the present stage, various standardization organizations have proposed the concept of Next Generation Network (NGN) so as to meet requirements of the current terminal users for more novel and more diversified multimedia services. On the basis of packet bearing networks, an IP Multimedia Subsystem (IMS) is introduced for the all Internet Protocol (IP) service network architecture.
In the IMS, a service profile stored in a Home Subscriber Server (HSS) is a set of user profile information, including user profile data associated with a service. A Serving-Call Session Control Function (S-CSCF) may obtain the service profile data of a user from the HSS via a pair of commands like Server-Assignment-Request/Server-Assignment-Answer (SAR/SAA). Alternatively, the HSS may update the changed service profile data to the S-CSCF via a pair of commands like Push-Profile-Request/Push-Profile-Answer (PPR/PPA).
The service profile further includes four parts: Public Identification, Core Network Service Authorization, Initial Filter Criteria (iFC), and Shared iFC Set.
An iFC is used for triggering a service and includes service triggering points, which describe in what a condition a received Session Initiation Protocol (SIP) message will be routed to which AS, i.e., in what a condition the subscriber's service may be performed.
In a service implementation flow of an AS, first, a user is registered with a network. At the same time, the user service profile information including the iFC is downloaded from the HSS to the S-CSCF serving the subscriber. Then, the user may initiate an associated SIP service request with his/her User Equipment (UE). The request passes through a Proxy-Call Session Control Function (P-CSCF) to reach its home S-CSCF. Then, the S-CSCF may find an iFC matching the initiator of the request, and forward the request directly or route the request to the corresponding Application Servers based on the content of the iFC included in the user service profile information. Finally, the AS may provide the associated service to the subscriber.
In practical applications, a user may often need to change the content of the user service profile, for example, he may subscribe to a new service, or cancel a subscribed service. Further, a subscribed service generally may be in an active state or in an inactive state. The user may often change the state of a subscribed service, for example, he may change the subscribed service from an active state to an inactive state, or vice versa. When the content of the subscriber's service profile changes, the iFC within the service profile will change correspondingly. When a new service is subscribed, a new iFC is added or some new service trigger points are added to an existing iFC. When a subscribed service is cancelled, the corresponding iFC is removed or some service trigger conditions are removed from an iFC. When a subscribed service is changed from the inactive state to the active state, the corresponding iFC is downloaded to the S-CSCF with which the user is registered. When an active service is changed to the inactive state, the corresponding iFC is removed from the S-CSCF with which the user is registered.
At this time, the HSS will send the updated service profile information of the user to the S-CSCF of the user via the PPR/PPA. The S-CSCF updates the stored service profile information of the user. Meanwhile, the S-CSCF may perform a synchronized data update for the UE and other IMS entities.
In the currently used synchronization schemes, based on the subscription to notification mechanism for the UE and other IMS entities that subscribed to the user's registration event, the update of the user's registration state is notified to the UE and other IMS entities having subscription to the registration event notification of the user from the S-CSCF via an SIP-based NOTIFY message.
The user's registration state refers to the registration state of the user in the network, for example, it may be a registered state or an unregistered state. When the user modifies the service profile information, the AS related to the newly subscribed or newly activated service can offer the service to the user timely only when having knowledge of the registration state of the user.
During research and implementation of the prior art, the inventors have found the disadvantage of the prior art as follows. After the user has registered with the network, when the user newly subscribes to or activates a new service, the AS related to the newly subscribed or newly activated service typically will not subscribe for the registration event notification of the user from the S-CSCF. Therefore, the AS cannot obtain the registration state of the user at the first time, which will prevent the AS from timely providing the newly subscribed service or newly activated service to the user.